Snow bikes share overlapping functionality with snowmobiles, and a comparison of the two types of vehicles reveals their relative strengths and weaknesses. Snow bikes are more easily able to operate in technical terrain, which is difficult terrain requiring a high level of technical skill for a snowmobile operator. Snow bikes can more easily ride through off-trail areas, such as carving through deep snow, traversing steep hills (also known as sidehill terrain), and threading through tight spaces, such as between the trees of forested areas. Snow bikes can also more easily navigate the sudden bumps and dips found in technical terrain. They can initiate turns with much less rider input than needed to initiate turns while riding a snowmobile. In fact, much of the off-trail and technical terrain that a snow bike can easily navigate would be difficult or impossible for a conventional snowmobile. The greater agility of a snow bike is made possible in part by having a narrower frame due to having a single ski, a narrower track which encounters less snow resistance, more nimble steering and handling, the ability of a snow bike to lean into a turn, better balance, and lighter weight.
For example, Forbes, U.S. Pat. No. 6,626,258 describes how heavy snowmobiles with outrigger skis cannot effectively traverse steep slopes, whereas snow bikes are very capable of traversing steep slopes.
However, existing snow bikes do have some shortcomings. The lack of fore to aft balance causes the ski to follow existing trails and dart (i.e., to move unpredictably). This lack of balance also does not allow the use of heavier more powerful engines typically found on snowmobiles. The on-trail and long-distance performance of snowmobiles can exceed that of snow bikes. The more comfortable rider position and the larger seating area of a snowmobile can make long trail trips of more than 100 miles more comfortable than with a snow bike. The larger and longer seat allows the snowmobile to comfortably carry a passenger in addition to the driver.
Therefore, snow bikes are often better suited to shorter, performance oriented, off-trail use, while snowmobiles can be better suited to longer journeys on more even, on-trail terrain, where fewer obstacles are encountered.
Single-ski snow bikes have gained in popularity and usability over the last few years due to the availability of better snow bike conversion kits that can convert dirt bikes into snow bikes by adding a front ski and a rear track. For example, Timbersled®, Yeti®, and Arctic Cat® sell conversion kits.
One benefit of snow bike conversion kits is having a vehicle that one can convert back and forth between a dirt bike and a snow bike, effectively providing year-round use by reusing many parts of the motorcycle, such as the engine, transmission, exhaust system, frame, handlebars, and controls.
Snow bike kits allow enhanced maneuverability compared to snowmobiles, but they lack the fore and aft balance of a typical motorcycle or snowmobile, consequently causing handling failures in high g-load situations, such as jumping.
The Timbersled® kit employs a snowmobile-style rear track suspension mounted under an elongated tunnel-style rear chassis. The tunnel and track tread extend rearward a distance of multiple feet, and attach in place of the bike's swing-arm. As is common in snow bike kit conversions, the Timbersled® kit uses a single front ski which is mounted in place of the motorcycle's front wheel. A chain and sprocket transfer power from the bike's engine to a chain-case that in turn drives a jackshaft. A disc brake provides the braking.
The Yeti® kit uses a lightweight molded carbon fiber tunnel with the use of aluminum in key places. Yeti® uses a twin-shock snowmobile-style rear suspension with FOX shocks, and the track is driven using a belt drive that is visible through a clear plastic cover on the outside of the tunnel. The Yeti® tunnel and track also extend rearward a distance of multiple feet.
While there are a lot of aftermarket track and ski kits that bolt onto a dirt bike, some companies sell a complete single-ski snow vehicle from the factory. The Arctic Cat® 450, for example, which is factory built and not a kit, still has many fundamental design features that are similar to snow bikes made from motorcycle conversion kits, such as having a tunnel and track tread that extend rearward a distance of multiple feet behind the driver.
However, kit-style snow bikes can lead to operational instability. For example, U.S. Pat. No. 6,234,263 describes the single ski snow bikes that are in the style of motorcycle kit conversions as having the major drawback of instability. U.S. Pat. Nos. 5,474,146, and 4,613,006 also highlight the problem of instability, both having a rearward extending track.